pigman1 wrote:
I really wouldn't worry about it. The change interval is predicated on the very worst conditions possible during their prescribed interval pulling the heaviest load on the worst roads with the worst grades. Drive gently and change it when you get home. We go 20,000 on a Cummins ISL and I test at each change. According to the testing, I could go considerably longer, and although you don't specify the make/model/year, 3000 miles between changes is quite short on today's modern engines.
I'm driving an 2001 Ford with the 7.3L diesel. I've only had it just over a year, it's my first diesel. I've read the high pressure oil pump is really hard on the oil. I'll be towing a trailer with a GVWR of 7500lbs. I will be towing through the rocky mountains on the trip, but also across the prairies.